9 Thermal Properties and Temperature 2022 J

Two thermometers, P and Q, give the same reading at room temperature.

The bulb of thermometer Q is wrapped in gauze and dipped in a beaker of water at room temperature.

Air at room temperature is blown over the two thermometer bulbs.

Which statement correctly describes and explains what happens?

• P reads higher than Q because bulb P absorbs energy from the air.

• P reads higher than Q because water evaporates from the gauze and cools bulb Q.

• P reads lower than Q because the wet gauze insulates bulb Q.

• P reads lower than Q because water evaporates from the gauze and warms bulb Q.

The diagram shows a liquid-in-glass thermometer.

A student wishes to check the marking of the upper fixed point on this thermometer.

What should she do?

• Put the bulb in a beaker of boiling sea water.

• Put the bulb in a beaker of boiling pure water.

• Put the bulb in a beaker of ice and salt.

• Put the bulb in a beaker of pure melting ice.

The diagram shows a liquid-in-glass thermometer.

Which physical property of the thermometer is used to measure temperature?

• expansion of glass

• expansion of liquid

• mass of glass

• mass of liquid

An engineer investigates the increase in temperature of the oil in a car engine when it is first switched on. Which row is correct?

(a)  

The iron cylinder of an engine is to be fitted into a piece of aluminium.

The outside diameter M of the iron cylinder is slightly larger than the diameter N of the hole in the aluminium.

What is the best action to fit the cylinder into the aluminium?

• Cool the aluminium and cool the iron.

• Cool the aluminium and heat the iron.

• Heat the aluminium and cool the iron.

• Heat the aluminium and heat the iron.

A solid in a closed container is heated until it completely melts.

Which diagram shows the shape and the volume of the solid before and after heating?

• 
• 
• 
• 

The diagram shows a liquid-in-glass thermometer. A student wishes to check the marking of the upper fixed point on this thermometer. What should she do?

• Put the bulb in a beaker of boiling sea water.

• Put the bulb in a beaker of boiling pure water.

• Put the bulb in a beaker of ice and salt.

• Put the bulb in a beaker of pure melting ice.

Water in a beaker gains thermal energy at a rate of 3000 W.

The water is at its boiling point.

The specific latent heat of vaporization of water is 2260 J/g.

How long does it take for 250 g of the water to vaporize?

• 12 s

• 188 s

• 332 s

• 750 s

A block of lead of mass 500 g is at its melting point.

The specific latent heat of fusion of lead = 23 kJ/kg.

How much energy is required to completely melt the block?

• 46 J

• 12 000 J

• 46 000 J

• 12 000 000 J

Four metal blocks at a temperature of 200 ⁰C are left to cool down to the same temperature.

The table gives the mass of each block and the energy it transfers to the surroundings as it cools.

Which two blocks are made of the same metal?

• 1 and 2

• 1 and 3

• 1 and 4

• 3 and 4